Standardization of Selected Medicinal Herbs from Kisii Region Used in Treatment of Diabetes, Malaria and Pneumonia

Abstract

The herbs used as phytomedicines for the treatment of diabetes, malaria and pneumonia in Kisii region, Southwest Kenya are Carissa spinarum, Urtica dioica, Warburgia ugandensis, Senna didymobotrya, Physalis Peruviana, Bidens pilosa, Leonotis nepetifolia and Toddalia asiatica. The objective of this study was to standardize the selected eight herbs. Leaf samples of these herbs were obtained from Kisii region, washed, air-dried and milled. Standardization parameters namely: phytochemical screening, heavy metal analysis, antimicrobial activity and identification of functional groups were studied. The pH levels of the aqueous extract were measured using a pH meter. Results showed that the pH values ranged from 5.27 to 7.50. Phytochemical studies indicated presence of saponins, tannins, flavonoids, steroids and terpenoids in eight herbs while alkaloids in two, cardiac glycoside in five and anthraquinones in one and all were confirmed by TLC. Heavy metal analysis was done by atomic absorption spectrometry. The results showed the heavy metal present as: Fe, Cr, Cu, Zn, Co, Mn, Ni, Pb, Cd and Hg. The biological activity of these herbs by well diffusion method indicated that hexane, dichloromethane, ethyl acetate and ethanol extracts against Staphylococcus aureus, Escherichia coli and Candida albicans, showed antimicrobial and antifungal activity. The FTIR spectra analysis indicated the functional groups present as: OH, CH2 and CH3, C-N, C=N, C=C, C=O, C-O, C≡N and N≡C. Therefore extracts from these herbs have a potential to control Staphylococcus aureus, Escherichia coli and Candida albicans. These findings if incorporated with the existing knowledge and experiences that the traditional healers have, could improve their utilization.